The present invention relates to data carriers in general, and more particularly to improvements in card-like data carriers. Still more particularly, the invention relates to improvements in flat card-like data carriers for storage of information which can be decoded by automatic decoding machines or readers and can be used as identification cards, credit cards, money substitute cards, time recording cards or for analogous purposes.
It is well known to utilize data carriers in the form of cards as a means for gaining access to restricted areas, as identification cards, as credit cards or the like. Such cards contain information which can be decoded by machines, e.g., by readers wherein the card is introduced into a slot for examination by automatic scanning or decoding equipment.
A card which is used as a substitute for cash contains a plurality of discrete data or bits of information each of which denotes a particular sum of money. A fresh or unused card stores information denoting the maximum selected sum of money, e.g., the sum of one hundred dollars. Such information consists of several discrete data or bits of information each of which denotes a smaller sum of money, e.g., one dollar. In other words, the total information on an unused card which serves as a substitute for cash is divisible into a given number of identical data each denoting a corresponding fraction of the maximum sum of money which is represented by the entire information on the unused card. Each of such plurality of data is assigned a discrete portion or area on the card, and each discrete portion can be treated to erase or cancel the information which is stored therein. The erasure or cancellation of information on discrete areas is effected at a testing or examining station and is equivalent to cash payment of the corresponding sum of money. The card is useless and can be discarded as soon as the erasure or cancellation of information on the last discrete portion is completed.
A card of the just outlined character cannot be used as a means for identifying the bearer if it is printed or otherwise manufactured in large numbers and each of such a large number of cards contains identical information, e.g., if each card can serve as a substitute for the same amount of money. Therefore, it is often desirable to issue individualized cards each of which stores information denoting a certain sum of money as well as additional information pertaining to the owner or authorized user or bearer of such card.
A time sheet or card can be used to record information pertaining to the times of the day, to the days of the week, etc. Such cards are insertable into suitable machines (e.g., clocks) which encode the time of the day and/or the day of the week and/or other information which is indicative of the time when the card was provided with or relieved of information. The information is normally stored in a form which can be decoded by an automatic reader.
Each and every one of the above enumerated data carriers must satisfy at least some, and preferably all, of the following requirements:
First of all, a data carrier should be constructed and assembled with a view to ensure that it cannot be readily manufactured by unauthorized persons. If the data carriers are used in lieu of cash, the time, effort and equipment needed for reintroduction or reencoding of previously erased information which denotes a given sum or money must be more expensive than the sum of money which is denoted by the reencoded information. In other words, tampering with such data carriers for the purpose of encoding information denoting given sums of money must be sufficiently expensive to deter the would-be forgers from attempting to encode cancelled information.
Secondly, the data carrier must be of the type which is capable of being mass-produced at a relatively low cost, and the nature of information which is encoded therein or which is to be encoded therein must be such that the information can be encoded and/or decoded by resorting to relatively simple and inexpensive machinery. For example, when a data carrier is to be used as a substitute for a given sum of money, the machine which handles such data carriers at a counter or the like must be less expensive than the clerk or another employee who would be in charge of accepting or handing out sums of money in the absence of data carriers.
Still further, the methods and/or machines for the making of data carriers should be sufficiently complex and/or expensive to deter all would-be forgers or imitators from investing the necessary capital and/or time. This applies especially for data carriers which are used as substitutes for cash.
The following constitute but a few of presently known data carriers which fail to satisfy the above-enumerated requirements:
(a) Data carriers which are provided with magnetic tracks for storage of information thereon. PA1 (b) Data carriers wherein the information is encoded in the form of holes or perforations. PA1 (c) Data carriers of transparent synthetic plastic material with imprinted opaque (black) indicia. PA1 (d) Data carriers with inductively readable non-visible metallic inserts. PA1 (e) Carriers with printed conductor tracks, including carriers with tracks acting not unlike high-frequency resonators. PA1 (f) Carriers with highly integrated circuits, for example, of the type disclosed in German Offenlegungsschrift No. 2,224,937. PA1 (g) Data carriers which embody optical reflectors or reflecting zones, for example, of the type disclosed in German Offenlegungsschrift No. 2,659,639. PA1 (h) Data carriers with information which constitutes a holograph. Data carriers of such type are disclosed in U.S. Pat. No. 3,643,216 granted Feb. 15, 1972 to Greenaway et al.
The data carriers (a) to (e) bear unidimensional or twodimensional information. Therefore, such data carriers can be readily copied by resorting to commercially available apparatus or machines. In other words, data carriers of the type (a), (b), (c), (d) and/or (e) can be readily falsified unless they are provided with additional means or are produced and/or treated in accordance with further techniques which prevent ready and inexpensive counterfeiting. One of such techniques involves the integration of a magnetic tape or strip into a data carrier which is provided with hard-to-copy data, i.e., with information which cannot be readily copied by forgers or cannot be copied at all. Data carriers with highly integrated circuits cannot be readily copied; however, their cost is extremely high. Data carriers which embody reflection zones or holographic information can be said to carry data in threedimensional form which cannot be readily copied by resorting to twodimensional copying equipment. Therefore, such data carriers cannot be readily forged. However, the cost of presently known data carriers bearing threedimensional information is often much too high for a number of uses so that the field of applications of such data carriers is rather limited.